O-rings made of natural or synthetic rubber are well known for use as sealing devices for the containment of various fluids including chemical solvents, gases and plasmas. The type of rubber used in a seal is chosen based on the type of fluid to be sealed and the temperature of the environment in which the seal is to be employed. Seals for corrosive fluids and strong solvents, or for high temperature applications often require the rubber to be a fluoroelastomer or perfluoroelastomer.
In semi-dynamic applications, wherein one of the surfaces in contact with the O-ring moves, the O-ring can shift and twist in its seat (i.e. the groove in which it is mounted) or the O-ring may be physically damaged or broken and fluid can then move around the seal and cause a leak. In the past, this problem has been partially solved by designing the seat to have a dovetail shaped cross-section, which more firmly holds the O-ring in place. However, it can be very difficult to install a seal into a dovetail shaped groove without damaging or twisting it. A seal which is damaged during installation or which is twisted in its seat during installation or in use can fail (i.e. leak) immediately or may have a shortened useful lifetime. Therefore, it would be an advantage to have a rubber seal which may easily be installed into a dovetail shaped seat and which, when installed, provides excellent semi-dynamic sealing properties.